[linux-2.6-block.git] / drivers / input / misc / rotary_encoder.c

/*
 * rotary_encoder.c
 *
 * (c) 2009 Daniel Mack <daniel@caiaq.de>
 * Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
 *
 * state machine code inspired by code from Tim Ruetz
 *
 * A generic driver for rotary encoders connected to GPIO lines.
 * See file:Documentation/input/rotary-encoder.txt for more information
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/rotary_encoder.h>
#include <linux/slab.h>

#define DRV_NAME "rotary-encoder"

struct rotary_encoder {
	struct input_dev *input;
	struct rotary_encoder_platform_data *pdata;

	unsigned int axis;
	unsigned int pos;

	unsigned int irq_a;
	unsigned int irq_b;

	bool armed;
	unsigned char dir;	/* 0 - clockwise, 1 - CCW */

	char last_stable;
};

static int rotary_encoder_get_state(struct rotary_encoder_platform_data *pdata)
{
	int a = !!gpio_get_value(pdata->gpio_a);
	int b = !!gpio_get_value(pdata->gpio_b);

	a ^= pdata->inverted_a;
	b ^= pdata->inverted_b;

	return ((a << 1) | b);
}

static void rotary_encoder_report_event(struct rotary_encoder *encoder)
{
	struct rotary_encoder_platform_data *pdata = encoder->pdata;

	if (pdata->relative_axis) {
		input_report_rel(encoder->input,
				 pdata->axis, encoder->dir ? -1 : 1);
	} else {
		unsigned int pos = encoder->pos;

		if (encoder->dir) {
			/* turning counter-clockwise */
			if (pdata->rollover)
				pos += pdata->steps;
			if (pos)
				pos--;
		} else {
			/* turning clockwise */
			if (pdata->rollover || pos < pdata->steps)
				pos++;
		}

		if (pdata->rollover)
			pos %= pdata->steps;

		encoder->pos = pos;
		input_report_abs(encoder->input, pdata->axis, encoder->pos);
	}

	input_sync(encoder->input);
}

static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
{
	struct rotary_encoder *encoder = dev_id;
	int state;

	state = rotary_encoder_get_state(encoder->pdata);

	switch (state) {
	case 0x0:
		if (encoder->armed) {
			rotary_encoder_report_event(encoder);
			encoder->armed = false;
		}
		break;

	case 0x1:
	case 0x2:
		if (encoder->armed)
			encoder->dir = state - 1;
		break;

	case 0x3:
		encoder->armed = true;
		break;
	}

	return IRQ_HANDLED;
}

static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
{
	struct rotary_encoder *encoder = dev_id;
	int state;

	state = rotary_encoder_get_state(encoder->pdata);

	switch (state) {
	case 0x00:
	case 0x03:
		if (state != encoder->last_stable) {
			rotary_encoder_report_event(encoder);
			encoder->last_stable = state;
		}
		break;

	case 0x01:
	case 0x02:
		encoder->dir = (encoder->last_stable + state) & 0x01;
		break;
	}

	return IRQ_HANDLED;
}

static int __devinit rotary_encoder_probe(struct platform_device *pdev)
{
	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	struct rotary_encoder *encoder;
	struct input_dev *input;
	irq_handler_t handler;
	int err;

	if (!pdata) {
		dev_err(&pdev->dev, "missing platform data\n");
		return -ENOENT;
	}

	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	input = input_allocate_device();
	if (!encoder || !input) {
		dev_err(&pdev->dev, "failed to allocate memory for device\n");
		err = -ENOMEM;
		goto exit_free_mem;
	}

	encoder->input = input;
	encoder->pdata = pdata;
	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	encoder->irq_b = gpio_to_irq(pdata->gpio_b);

	/* create and register the input driver */
	input->name = pdev->name;
	input->id.bustype = BUS_HOST;
	input->dev.parent = &pdev->dev;

	if (pdata->relative_axis) {
		input->evbit[0] = BIT_MASK(EV_REL);
		input->relbit[0] = BIT_MASK(pdata->axis);
	} else {
		input->evbit[0] = BIT_MASK(EV_ABS);
		input_set_abs_params(encoder->input,
				     pdata->axis, 0, pdata->steps, 0, 1);
	}

	err = input_register_device(input);
	if (err) {
		dev_err(&pdev->dev, "failed to register input device\n");
		goto exit_free_mem;
	}

	/* request the GPIOs */
	err = gpio_request(pdata->gpio_a, DRV_NAME);
	if (err) {
		dev_err(&pdev->dev, "unable to request GPIO %d\n",
			pdata->gpio_a);
		goto exit_unregister_input;
	}

	err = gpio_direction_input(pdata->gpio_a);
	if (err) {
		dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
			pdata->gpio_a);
		goto exit_unregister_input;
	}

	err = gpio_request(pdata->gpio_b, DRV_NAME);
	if (err) {
		dev_err(&pdev->dev, "unable to request GPIO %d\n",
			pdata->gpio_b);
		goto exit_free_gpio_a;
	}

	err = gpio_direction_input(pdata->gpio_b);
	if (err) {
		dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
			pdata->gpio_b);
		goto exit_free_gpio_a;
	}

	/* request the IRQs */
	if (pdata->half_period) {
		handler = &rotary_encoder_half_period_irq;
		encoder->last_stable = rotary_encoder_get_state(pdata);
	} else {
		handler = &rotary_encoder_irq;
	}

	err = request_irq(encoder->irq_a, handler,
			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(&pdev->dev, "unable to request IRQ %d\n",
			encoder->irq_a);
		goto exit_free_gpio_b;
	}

	err = request_irq(encoder->irq_b, handler,
			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(&pdev->dev, "unable to request IRQ %d\n",
			encoder->irq_b);
		goto exit_free_irq_a;
	}

	platform_set_drvdata(pdev, encoder);

	return 0;

exit_free_irq_a:
	free_irq(encoder->irq_a, encoder);
exit_free_gpio_b:
	gpio_free(pdata->gpio_b);
exit_free_gpio_a:
	gpio_free(pdata->gpio_a);
exit_unregister_input:
	input_unregister_device(input);
	input = NULL; /* so we don't try to free it */
exit_free_mem:
	input_free_device(input);
	kfree(encoder);
	return err;
}

static int __devexit rotary_encoder_remove(struct platform_device *pdev)
{
	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;

	free_irq(encoder->irq_a, encoder);
	free_irq(encoder->irq_b, encoder);
	gpio_free(pdata->gpio_a);
	gpio_free(pdata->gpio_b);
	input_unregister_device(encoder->input);
	platform_set_drvdata(pdev, NULL);
	kfree(encoder);

	return 0;
}

static struct platform_driver rotary_encoder_driver = {
	.probe		= rotary_encoder_probe,
	.remove		= __devexit_p(rotary_encoder_remove),
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	}
};

static int __init rotary_encoder_init(void)
{
	return platform_driver_register(&rotary_encoder_driver);
}

static void __exit rotary_encoder_exit(void)
{
	platform_driver_unregister(&rotary_encoder_driver);
}

module_init(rotary_encoder_init);
module_exit(rotary_encoder_exit);

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION("GPIO rotary encoder driver");
MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
73969ff0 DM	1	/*
	2	* rotary_encoder.c
	3	*
	4	* (c) 2009 Daniel Mack <daniel@caiaq.de>
e70bdd41	5	* Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
73969ff0 DM	6	*
	7	* state machine code inspired by code from Tim Ruetz
	8	*
	9	* A generic driver for rotary encoders connected to GPIO lines.
395cf969	10	* See file:Documentation/input/rotary-encoder.txt for more information
73969ff0 DM	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License version 2 as
	14	* published by the Free Software Foundation.
	15	*/
	16
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/init.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/input.h>
	22	#include <linux/device.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/gpio.h>
	25	#include <linux/rotary_encoder.h>
5a0e3ad6	26	#include <linux/slab.h>
73969ff0 DM	27
	28	#define DRV_NAME "rotary-encoder"
	29
	30	struct rotary_encoder {
73969ff0 DM	31	struct input_dev *input;
73969ff0 DM	32	struct rotary_encoder_platform_data *pdata;
bd3ce655 HS	33
	34	unsigned int axis;
	35	unsigned int pos;
	36
	37	unsigned int irq_a;
	38	unsigned int irq_b;
	39
	40	bool armed;
	41	unsigned char dir; /* 0 - clockwise, 1 - CCW */
e70bdd41 JH	42
e70bdd41 JH	43	char last_stable;
73969ff0 DM	44	};
73969ff0 DM	45
521a8f5c	46	static int rotary_encoder_get_state(struct rotary_encoder_platform_data *pdata)
73969ff0	47	{
73969ff0 DM	48	int a = !!gpio_get_value(pdata->gpio_a);
73969ff0 DM	49	int b = !!gpio_get_value(pdata->gpio_b);
73969ff0 DM	50
	51	a ^= pdata->inverted_a;
	52	b ^= pdata->inverted_b;
73969ff0	53
521a8f5c JH	54	return ((a << 1) \| b);
521a8f5c JH	55	}
73969ff0	56
521a8f5c JH	57	static void rotary_encoder_report_event(struct rotary_encoder *encoder)
	58	{
	59	struct rotary_encoder_platform_data *pdata = encoder->pdata;
73969ff0	60
521a8f5c JH	61	if (pdata->relative_axis) {
	62	input_report_rel(encoder->input,
	63	pdata->axis, encoder->dir ? -1 : 1);
	64	} else {
	65	unsigned int pos = encoder->pos;
	66
	67	if (encoder->dir) {
	68	/* turning counter-clockwise */
bd3ce655	69	if (pdata->rollover)
521a8f5c JH	70	pos += pdata->steps;
	71	if (pos)
	72	pos--;
	73	} else {
	74	/* turning clockwise */
	75	if (pdata->rollover \|\| pos < pdata->steps)
	76	pos++;
73969ff0	77	}
73969ff0	78
521a8f5c JH	79	if (pdata->rollover)
	80	pos %= pdata->steps;
	81
	82	encoder->pos = pos;
	83	input_report_abs(encoder->input, pdata->axis, encoder->pos);
	84	}
	85
	86	input_sync(encoder->input);
	87	}
	88
	89	static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
	90	{
	91	struct rotary_encoder *encoder = dev_id;
	92	int state;
	93
	94	state = rotary_encoder_get_state(encoder->pdata);
	95
	96	switch (state) {
	97	case 0x0:
	98	if (encoder->armed) {
	99	rotary_encoder_report_event(encoder);
	100	encoder->armed = false;
	101	}
73969ff0 DM	102	break;
	103
	104	case 0x1:
	105	case 0x2:
	106	if (encoder->armed)
	107	encoder->dir = state - 1;
	108	break;
	109
	110	case 0x3:
bd3ce655	111	encoder->armed = true;
73969ff0 DM	112	break;
	113	}
	114
	115	return IRQ_HANDLED;
	116	}
	117
e70bdd41 JH	118	static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
	119	{
	120	struct rotary_encoder *encoder = dev_id;
	121	int state;
	122
	123	state = rotary_encoder_get_state(encoder->pdata);
	124
	125	switch (state) {
	126	case 0x00:
	127	case 0x03:
	128	if (state != encoder->last_stable) {
	129	rotary_encoder_report_event(encoder);
	130	encoder->last_stable = state;
	131	}
	132	break;
	133
	134	case 0x01:
	135	case 0x02:
	136	encoder->dir = (encoder->last_stable + state) & 0x01;
	137	break;
	138	}
	139
	140	return IRQ_HANDLED;
	141	}
	142
73969ff0 DM	143	static int __devinit rotary_encoder_probe(struct platform_device *pdev)
	144	{
	145	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	146	struct rotary_encoder *encoder;
	147	struct input_dev *input;
e70bdd41	148	irq_handler_t handler;
73969ff0 DM	149	int err;
73969ff0 DM	150
06ee3d3c HS	151	if (!pdata) {
06ee3d3c HS	152	dev_err(&pdev->dev, "missing platform data\n");
73969ff0 DM	153	return -ENOENT;
	154	}
	155
	156	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	157	input = input_allocate_device();
	158	if (!encoder \|\| !input) {
	159	dev_err(&pdev->dev, "failed to allocate memory for device\n");
	160	err = -ENOMEM;
	161	goto exit_free_mem;
	162	}
	163
	164	encoder->input = input;
	165	encoder->pdata = pdata;
	166	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	167	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
	168
	169	/* create and register the input driver */
	170	input->name = pdev->name;
	171	input->id.bustype = BUS_HOST;
	172	input->dev.parent = &pdev->dev;
bd3ce655 HS	173
	174	if (pdata->relative_axis) {
	175	input->evbit[0] = BIT_MASK(EV_REL);
	176	input->relbit[0] = BIT_MASK(pdata->axis);
	177	} else {
	178	input->evbit[0] = BIT_MASK(EV_ABS);
	179	input_set_abs_params(encoder->input,
	180	pdata->axis, 0, pdata->steps, 0, 1);
	181	}
73969ff0 DM	182
	183	err = input_register_device(input);
	184	if (err) {
	185	dev_err(&pdev->dev, "failed to register input device\n");
	186	goto exit_free_mem;
	187	}
	188
	189	/* request the GPIOs */
	190	err = gpio_request(pdata->gpio_a, DRV_NAME);
	191	if (err) {
	192	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	193	pdata->gpio_a);
	194	goto exit_unregister_input;
	195	}
	196
5deeac99 AC	197	err = gpio_direction_input(pdata->gpio_a);
	198	if (err) {
	199	dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
	200	pdata->gpio_a);
	201	goto exit_unregister_input;
	202	}
	203
73969ff0 DM	204	err = gpio_request(pdata->gpio_b, DRV_NAME);
	205	if (err) {
	206	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	207	pdata->gpio_b);
	208	goto exit_free_gpio_a;
	209	}
	210
5deeac99 AC	211	err = gpio_direction_input(pdata->gpio_b);
	212	if (err) {
	213	dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
	214	pdata->gpio_b);
	215	goto exit_free_gpio_a;
	216	}
	217
73969ff0	218	/* request the IRQs */
e70bdd41 JH	219	if (pdata->half_period) {
	220	handler = &rotary_encoder_half_period_irq;
	221	encoder->last_stable = rotary_encoder_get_state(pdata);
	222	} else {
	223	handler = &rotary_encoder_irq;
	224	}
	225
	226	err = request_irq(encoder->irq_a, handler,
e0d5f4c3	227	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING,
73969ff0 DM	228	DRV_NAME, encoder);
	229	if (err) {
	230	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	231	encoder->irq_a);
	232	goto exit_free_gpio_b;
	233	}
	234
e70bdd41	235	err = request_irq(encoder->irq_b, handler,
e0d5f4c3	236	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING,
73969ff0 DM	237	DRV_NAME, encoder);
	238	if (err) {
	239	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	240	encoder->irq_b);
	241	goto exit_free_irq_a;
	242	}
	243
	244	platform_set_drvdata(pdev, encoder);
	245
	246	return 0;
	247
	248	exit_free_irq_a:
	249	free_irq(encoder->irq_a, encoder);
	250	exit_free_gpio_b:
	251	gpio_free(pdata->gpio_b);
	252	exit_free_gpio_a:
	253	gpio_free(pdata->gpio_a);
	254	exit_unregister_input:
	255	input_unregister_device(input);
	256	input = NULL; /* so we don't try to free it */
	257	exit_free_mem:
	258	input_free_device(input);
	259	kfree(encoder);
	260	return err;
	261	}
	262
	263	static int __devexit rotary_encoder_remove(struct platform_device *pdev)
	264	{
	265	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
	266	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	267
	268	free_irq(encoder->irq_a, encoder);
	269	free_irq(encoder->irq_b, encoder);
	270	gpio_free(pdata->gpio_a);
	271	gpio_free(pdata->gpio_b);
	272	input_unregister_device(encoder->input);
	273	platform_set_drvdata(pdev, NULL);
	274	kfree(encoder);
	275
	276	return 0;
	277	}
	278
	279	static struct platform_driver rotary_encoder_driver = {
	280	.probe = rotary_encoder_probe,
	281	.remove = __devexit_p(rotary_encoder_remove),
	282	.driver = {
	283	.name = DRV_NAME,
	284	.owner = THIS_MODULE,
	285	}
	286	};
	287
	288	static int __init rotary_encoder_init(void)
	289	{
	290	return platform_driver_register(&rotary_encoder_driver);
	291	}
	292
	293	static void __exit rotary_encoder_exit(void)
	294	{
	295	platform_driver_unregister(&rotary_encoder_driver);
	296	}
	297
	298	module_init(rotary_encoder_init);
	299	module_exit(rotary_encoder_exit);
	300
301	MODULE_ALIAS("platform:" DRV_NAME);
302	MODULE_DESCRIPTION("GPIO rotary encoder driver");
e70bdd41	303	MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
73969ff0	304	MODULE_LICENSE("GPL v2");